solar pv grid tie = grid-tied, grid-tied synchronous inverter, distributed generation, decentralised generator, decentralized generation = Specialised inverter synchronised to mains frequency and voltage and able to pump energy directly into the grid as part of a decentralised/distributed generation scheme. Allows energy to be drawn locally by mains-connected loads, with excess typically automatically 'spilling' to the grid, deferring centralised (possibly fossil-fuel) generation elsewhere. Typically has safety features such as disconnection from the grid if its parameters fall out of tolerance (frequency/voltage) to protect engineers working on the lines (say) after a blackout. Can range in size from a few Watts to MegaWatts, and can typically be paralleled/'stacked' easily.

closeup = close-up/macro; tightly framed and imaged at a relatively large scale